In general, an outdoor unit of an air-conditioning apparatus has a casing that is formed by an outer shell panel constituting the front surface and a part of the side surface, a top panel constituting the top surface, and a side panel constituting a part of the side surface. As for the outer shell panel, a sheet metal component constituting a single panel is bent in a curved shape at right angles to form the front surface of the outdoor unit and the side surface of the outdoor unit. This outer shell panel is combined with the side panel, and the top panel is mounted to the upper side of these panels to thereby complete the casing.
The top panel is placed over the outside of the upper side of the bent portion of the outer shell panel (hereinafter, the bent portion is referred to as upper corner bend portion). Because the outer shell panel is formed by bending a sheet metal component in a curved shape at right angles, as this curved portion contracts, wrinkles form in the upper corner bend portion. Accordingly, there has been proposed an outdoor unit in which a cut is made in the upper corner bend portion to reduce its height, thereby minimizing formation of wrinkles (see, for example, Patent Literature 1).